class_docstr: Handles tokenization history.
code: def __init__(self, opt, **kwargs):
      self.sep_last_utt = opt.get("sep_last_utt", False)
      super().__init__(opt, **kwargs)
  
imports: import os
  from collections import deque
  from typing import Optional
  import torch
  from parlai.agents.bert_ranker.bert_dictionary import BertDictionaryAgent
  from parlai.agents.bert_ranker.helpers import BertWrapper, MODEL_PATH
  from parlai.core.opt import Opt
  from parlai.core.params import ParlaiParser
  from parlai.core.torch_agent import History
  from parlai.core.torch_classifier_agent import TorchClassifierAgent
  from parlai.utils.io import PathManager
  from parlai.utils.misc import warn_once
  from parlai.zoo.bert.build import download
label_desc: Use image node_id 1 to create a new BertClassifierHistory object from inherited base classes: History with example: obj = BertClassifierHistory(opt)